More VROOM, plus fuel-efficiency!

The Benefits

Improved vehicle performance
Put simply, a six-speed transmission uses its wider spread of gears to provide improved acceleration at the bottom end and an overdrive gear at the top end for fuel efficiency. With more gear choices, your overall driving experience is enhanced at any speed.

Increased fuel efficiency and lower CO_² emissions
The sixth gear – overdrive in a six-speed transmission – helps reduce engine revolutions (RPM) during highway cruising. Reduced RPM increases fuel efficiency because your engine doesn’t have to work as hard, or turn over as often. With a sixth (overdrive) gear in your Chevrolet six-speed transmission vehicle, you’re saving money at the pump and reducing CO_² emissions.

Quieter
The low RPM of the sixth overdrive gear also means less engine noise, so your ride is quieter.

Better
Sometimes a comparison makes things clearer. So if you’re wondering whether there’s a real benefit to a six-speed vs. a four- or five-speed transmission, here are some contrasts.

In performance, according to Mark Gilmore, GM global engineering director for manual transmissions, “Six-speed transmissions inherently offer increased flexibility over four- or five-speed transmissions to fine tune the gear ratios to specific engine characteristics and vehicle performance targets.”¹

In fuel consumption, while fuel savings will vary by Chevrolet model, typically a six-speed automatic transmission will increase fuel efficiency by up to four percent compared to Chevrolet 4-speed automatic transmissions, which already offer excellent fuel efficiency.



Gear Talk -- Tech Talk about vehicle performance

To explain how a six-speed transmission gives you better acceleration, we first have to talk about something you may not hear about every day: gear ratio spread.

Gear ratio is the number of times that a vehicle’s driveshaft turns for every one wheel rotation. A six-speed transmission means you have six gears, giving you a wide ratio spread. And because of the wide ratio spread in Chevrolet’s six-speed transmission, first gear is a very high ratio (sometimes called a “steep” gear). A high ratio, or “steep” gear, means you’ll get very brisk acceleration or “launch” when you start from a full stop.

What’s the overall effect of the wide ratio spread? As Jim Lanzon, executive director of transmission engineering for GM Powertrain, says, “a six-speed transmission uses the six gears to evenly distribute the engine’s torque as you accelerate, and then settle at an overdrive ratio.”²

And, with the six-speed, “smaller ‘steps’ are used between the gears, compared to a conventional four-speed automatic.”³  As a result, the transmission accesses the best gear for the speed you’re driving and the road conditions. When you’re on a hill, for example, you won’t sense that your transmission is trying to “hunt” for the right gear.

More
Six-speed transmissions are offered in both automatic and manual, and six-speed automatic technology is now available in almost all Chevrolet cars, trucks, SUVs and crossovers in our 2012 line-up, in front, rear and all-wheel drive applications.

Here is a list of 2012 Chevrolet vehicles that offer six-speed automatic transmissions.

Chevrolet Avalanche
Chevrolet Camaro
Chevrolet Corvette
Chevrolet Cruze
Chevrolet Equinox
Chevrolet Express
Chevrolet Impala
Chevrolet Malibu
Chevrolet Orlando
Chevrolet Silverado 1500
Chevrolet Silverado HD
Chevrolet Sonic
Chevrolet Suburban
Chevrolet Tahoe
Chevrolet Traverse

Sources

¹ 12 Chevrolet Models Offer Fuel-Saving, Six-speed Automatic Transmissions for 2011 Model Year. GM Communications. Media.gm.com.  2010-05-06.

^{2, 3} GM Launches More Fuel-Saving Six-Speed Automatic Transmissions. GM Communications. Media.gm.com.  2006-05-18.